Patients are often required to wear casts or braces over long periods of time. This limits access to the treatment area and prevents medical treatment. Atrophy of the underlying muscle tissue is a common problem. Because of the inaccessibility of the treatment area, drug delivery is made difficult, and traditional methods of drug delivery by injection must be used.
The use of iontophoresis and electrotherapy for drug delivery has been known and recognized as an acceptable form of treatment. Prior devices utilizing iontophoresis and/or electrophoresis were unable to simultaneously treat large areas systematically in an anatomical circumference or be incorporated under casts or braces, with the exception of the inventor's previous U.S. Pat. No. 5,344,384.
Furthermore, the previously known devices did not provide the availability of multiple treatment protocols.
Many iontophoretic drug delivery devices have been described in the patent literature, including U.S. Pat. Nos.:
5,387,189 to Gory et al; PA0 5,358,483 to Sibalis; PA0 5,356,632 to Gross et al; PA0 5,312,325 to Sibalis; PA0 5,279,544 to Gross et al; PA0 5,167,479 to Sibalis; PA0 5,156,591 to Gross et al; PA0 5,135,479 to Sibalis et al; PA0 5,088,977 to Sibalis; PA0 5,057,072 to Phipps; PA0 5,053,001 to Reller et al; PA0 4,942,883 to Newman; PA0 4,752,285 to Patelenz et al; PA0 4,734,090 to Sibalis; PA0 4,731,049 to Parsi; PA0 4,622031 to Sibalis; PA0 4,325,367 to Tapper; and PA0 4,164,226 to Tapper.
The need to provide a broad spectrum of treatment protocols suited to the injury and/or medical condition of the patient requires a system having a high degree of drug flow controllability.
Controlled delivery of drugs through the skin by use of transdermal patches is well known in the prior art. Passive transdermal drug delivery patches provide advantages over other drug delivery methods by delivering the drug directly to the affected area. This method is advantageous over other known methods such as oral administration which necessitates absorption through the digestive tract, or intravenous drug administration which involves needles. Currently, certain patient types present serious problems to traditional IV techniques. These patients include: patients with blood disorders, immuno-compromised patients, patients with renal dysfunction, patients with vein disorders or deep set veins and small children. It is estimated that patients in the above categories represent at least 20-25% of all hospital patients. Both oral and intravenous administration involve administering high doses of drug to the body at one time, systemically affecting the whole body with the pharmaceutical. These high levels of drug concentration in the blood can create toxic side effects. In addition, only a very small percentage of the drug reaches the affected target area in the body.
There has been a trend toward demands for new methods of self-administered prescription pharmaceuticals such as time-release oral medications and transdermal patches. Transdermal delivery provides medication specifically to the area of treatment in the exact quantities required. However, the number of passive transdermal drug delivery patches available, such as the nicotine, estrogen and nitroglycerine patches, are limited because they are effective only with small-molecule drugs. Many of the newly developed proteins and peptide drugs are too large to be delivered through passive transdermal patches, forcing pharmaceutical companies to seek advanced delivery technology such as electrical assist (ionotophoresis) for large-molecule drugs.
Iontophoresis is a technique employed for enhancing the flux of ionized substances through membranes by application of electric current. The principal mechanisms by which iontophoresis enhances molecular transport across the skin are (a) repelling a charged ion from an electrode of the same charge, (b) electroosmosis, the convective movement of solvent that occurs through a charged pore in response the preferential passage of counter-ions when an electric field is applied or (c) increase skin permeability due to application of electrical current.
Many drugs have been formulated for commercial use in the pharmaceutical industry employing iontophoresis. Both passive and electrical assist transdermal drug delivery necessitate wearing transdermal patches made of synthetic substances consisting of a high co-polymer content for long periods of time, often causing skin reactions due to the body's rejection of the membrane as being foreign to the skin. Also, most membrane patches require a specific drug designed toward use with a particular membrane for a specified limited time of usage.
Therefore, it would be desirable to overcome the above-mentioned disadvantages and provide a transdermal active drug delivery system that would deliver large-molecule drugs in an efficient manner directly to the affected site, even under a cast or brace, while allowing long term skin contact without causing skin irritation.